Schroeder’s body was found in his trailer early Friday morning in the Brookside Mobile RV Park in the 9800 block of State Avenue. His 2006 Chevrolet Colorado pickup was torched Friday night in a rural area north of Arlington.

There is no known connection between Schroeder’s killing and that of another person whose body was found near a burned-out car Saturday in the Lake Roesiger area, Snohomish County Sheriff’s Office spokeswoman Shari Ireton said Monday.

The pickup was found in the 24300 block of 19th Avenue NE, near the 236th Street exit from I-5.

No suspects had been arrested as of Monday evening.

Detectives were continuing to try to determine a motive for Schroeder’s killing.

“We just don’t have any idea yet,” Lamoureux said.

One of Schroeder’s grandsons said he found him on the floor of his ransacked trailer after stopping to check on him, officials said. It was unclear how long Schroeder had been dead.

“We have more work to do inside the trailer,” Lamoureux said. “We have not had family into the trailer to tell us if anything was missing or not.”

Two death investigations

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Schroeder was a registered sex offender who spent 18 years in prison, according to state Department of Corrections records.

In 1985, he was convicted in Snohomish County Superior Court of multiple counts of statutory rape, indecent liberties and communication with a minor for immoral purposes. The crimes, involving 20 victims, took place between 1980 and 1983, the sheriff’s office reported in 2004. His victims included girls ages 8 to 14.

His last conviction came in February 2011 when he pleaded guilty to failing to register as a sex offender.

Police on Friday asked for help in finding Schroeder’s truck, which they considered stolen.

Someone called 911 about 10:45 p.m. Friday to report a possible house fire at the rural address north of Arlington. It turned out to be Schroeder’s vehicle.

Firefighters were still en route when emergency dispatchers were told it was actually a vehicle fire, said Greg Osborne, the battalion chief on duty that night with the North County Regional Fire Authority.

Silvana fire crews were first on scene, he said. They found the truck parked behind an abandoned house.

“The vehicle was fully involved in fire at that time,” he said.

Crews extinguished the fire, but the truck was destroyed, he said.

A Snohomish County sheriff’s deputy who was on scene ran the license plate.

“We turned it over to law enforcement,” Osborne said.

Investigators also were summoned from the Snohomish County Fire Marshal’s Office, per standard procedure.

Meanwhile, sheriff’s Major Crimes detectives spent much of the weekend investigating a suspicious death discovered along the 7300 block of Woods Creek Road, a few miles south of Lake Roesiger.

Somebody called 911 about 3:30 p.m. Saturday to report finding a body and a burned-out car. The car’s make and model were not released Monday.

The body was transferred to the Snohomish County Medical Examiner’s Office for determination of identity and cause of death, Ireton said.